> I want to write the inside function (3^(x[i]+x[j])) in a more condensed form > cause this will help me when the multiple summations are more than two
indices<-c(i,j) #or whatever you want 3^sum( x[indices] ) S Ellison ******************************************************************* This email and any attachments are confidential. Any use...{{dropped:8}} ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.